JPH09194610A - Prepreg and laminated sheet prepared by using resin composition with low dielectric constant and low dielectric dissipation factor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prepreg consisting of a resin compsn. with excellent dielectric characteristics such as dielectric const. and dielectric dissipation factor and good heat resistance, mechanical processability and flame resistance. SOLUTION: This prepreg is prepd. by impregnating a base material with an epoxy resin compsn. consisting of an epoxy resin being at least one kind of epoxy resin contg. at least two epoxy groups in one molecule and further containing at least one brominated epoxy resin, an epoxy resin curing agent being a copolymer wherein styrene and maleic anhydride are essential components, a flexibilizer which can decrease the glass transition temp. of the compsn. by 10-20 deg.C by compounding it in the compsn., and a solvent with a b.p. of at least 100 deg.C being a solvent for these components as essential components. The mean bromination ratio in the whole epoxy resin is at least 30wt.% and the mean epoxy equivalent is at most 500 and the mean hydroxyl group concn. is at most 1×10<-3> mole/g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg and a laminated plate for an electric insulating material, which are made of a resin composition having excellent dielectric properties such as a dielectric constant and a dielectric loss tangent, and having excellent heat resistance, machinability and flame resistance. It is a thing. The resin composition used in the present invention has good impregnability into a substrate, has a low dielectric constant and dielectric loss tangent, and has heat resistance, chemical resistance and combustion resistance, and is excellent in machinability. It is suitable for use in electrical laminate applications. A laminated board using the resin composition,
Since it has excellent dielectric properties, it enables fine patterning, high signal propagation speed, and low loss of high-frequency signals due to high-density mounting of electronic parts. It is possible to reduce the thickness and weight of the insulating layer.

In addition, because of its high heat resistance, the strength of the material is maintained in the manufacturing process in which the substrate itself is exposed to high temperature conditions such as surface mounting, which is becoming mainstream in recent years,
Since the amount of expansion and contraction can be reduced, the manufacturing process of the electrical laminate can be made more stable.

[0003]

2. Description of the Related Art With the development of an information-oriented society, electronic devices such as computers are becoming lighter, thinner, smaller, and more sophisticated. In the printed wiring board field,
In the same tendency, there are strong demands for higher multilayer, thinner, and smaller size, and the demands for increased wiring density, higher processing speed, and lower transmission loss of high frequency are required for the substrate material and its manufacture. Subject to technology.

In computer calculation, the signal propagation speed is inversely proportional to the square root of the dielectric constant of the material, and the attenuation of the transmitted signal is proportional to the dielectric loss tangent.
It is necessary to keep these values as low as possible in a substrate material for high-speed calculation or handling high-frequency signals. As an attempt to suppress the dielectric constant to a low level, various studies have been conducted from the viewpoint of changing the composition and skeleton of the base resin and the surface of the base material, but a sufficient value has not been obtained yet.

As a printed wiring board for electronic equipment,
Up to now, laminated boards using epoxy resin have been widely used. However, with the recent increase in packaging density in electronic equipment, the density of pattern wiring has been increased, the surface mounting method has been changed, and the signal propagation speed has increased and the frequency of signals to be handled has increased, resulting in a low dielectric constant and a low dielectric loss tangent. At the same time, there is a strong demand for improvement in heat resistance, and various studies have been made in terms of resin composition, base material and the like.

Among the radical copolymers, the copolymer containing styrene and maleic anhydride as essential components has its own characteristics, namely, thermal stability, high melt viscosity and high melting point, and various organic solvents. It is used in many fields due to its solubility. As a typical example that is already known, a coating composition obtained by kneading and pulverizing an epoxy resin and the above copolymer (Japanese Patent Laid-Open No. 47-8087), a flexible epoxy resin, the flexibility of the above copolymer, etc. Printed wiring board (JP-A-49-10947)
6), a resin composition for a laminate (JP-A-2-127415), which comprises an epoxy resin, the above copolymer, a resin having a polymerizable unsaturated group, and a polymerizable vinyl monomer. Japanese Unexamined Patent Publication No. Sho 47-8087 is a composition for coating composition which is partially cured and pulverized.
No. 09476 requires an acrylonitrile butadiene copolymer as a reactive epoxy diluent for forming a flexible substrate, which is different from the processability improvement of the rigid substrate of the present invention. Japanese Unexamined Patent Publication No. 2-127415 is for a so-called wet process that does not contain a solvent other than a polymerizable vinyl monomer, cannot be applied to a dry process using an organic solvent that is usually used, and has a limited application range. It is a thing.

In a substantial two-component system in which only a copolymer containing styrene and maleic anhydride as essential components is used as a curing agent for an epoxy resin, the glass transition temperature of the cured product is very high, and the glass transition temperature of 200 ° C. is large. It often goes over. For this reason, the cured product becomes brittle, and when it is used as a laminated plate, the strength and the machinability are significantly deteriorated. In particular, the increase in hole inner wall roughness and plating penetration due to the deterioration of drill workability significantly reduces the insulation reliability in the recent fine patterning where the clearance between the through hole and the inner layer conductor or between the through holes is sandwiched. . In addition, since the plated shape in the hole becomes distorted, the connection reliability is poor. Therefore, it has never been used for electrical laminates.

[0008]

Most of the epoxy resin laminates to date are mainly composed of an epoxy resin based on an amine,
It is manufactured by laminating and heat-molding an impregnated base material that has been semi-cured with a phenol-based or acid-anhydride-based curing agent, but in recent years there has been a strong demand for low dielectric properties and severe manufacturing processes such as surface mounting. The current situation is that sufficient characteristic values have not been obtained in response to this. Further, from the viewpoint of dielectric properties, heat resistance, etc., a laminated board using a polyimide resin, a polyphenylene ether resin, a polytetrafluoroethylene resin, etc. has been proposed, but the price is high, and the moldability and processability are high. It has a relatively difficult problem and cannot be widely deployed for consumer use. From these, there has been a demand for a laminated plate which is relatively inexpensive and has excellent dielectric properties and high heat resistance, which is applicable to high density electronic parts and surface mounting.

[0009]

Means for Solving the Problems As a result of various studies, the present inventors have used a copolymer of a specific styrene and maleic anhydride as an essential curing agent for a specific epoxy resin, and have a specific flexibility. An epoxy resin composition using a specific solvent, which contains an imparting agent, has good impregnating properties and coating properties on a substrate, and is sufficiently applicable to electrical laminated board applications. It was found that a laminated sheet using the product has a low dielectric constant and a low dielectric loss tangent, has high heat resistance, has sufficient machinability, and is capable of imparting flame retardancy. It came to completion.

That is, the present invention is one or two or more epoxy resins having two or more epoxy groups in one molecule, and the average bromine content in all epoxy resins is 30% by weight or more, the average epoxy An epoxy resin (I) having an equivalent hydroxyl group of 500 or less and an average hydroxyl group concentration of 1 × 10 ⁻³ mol / g or less, a copolymer having styrene and maleic anhydride as essential components, and a molar ratio of styrene and maleic anhydride. But 9:
1 to 5: 5, acid value 100 to 600 mgKOH / g, number average molecular weight 1000 to 3000, a copolymer having at least one acid anhydride group in one molecule as a main curing agent, and acid for epoxy group The molar ratio of the anhydride group is in the range of 0.3 to 1.5, by blending the epoxy resin curing agent (II), the composition comprising the epoxy resin (I) and the curing agent (II) , A flexibility-imparting agent (III) capable of lowering the glass transition temperature by 10 to 20 ° C., and a resin (I) having a boiling point of 100 ° C. or higher, the curing agent (II) and a solvent of the styrene compound (III) ( IV), a prepreg obtained by impregnating a base material with an epoxy resin composition containing the essential component, and a low dielectric constant, low dielectric loss tangent and high heat resistance formed by laminating and molding using the prepreg, and excellent machinability It is a laminated board for an electric insulating material.

The epoxy resin (I) of the present invention is described in claims.
One having two or more epoxy groups in one molecule of or
Two or more types of epoxy resin, average of all epoxy resins
ROM content is 30% by weight or more, average epoxy equivalent is 500 or less
And the average hydroxyl group concentration is 1 x 10 ^-3It is below mol / g.
If it is applicable to this epoxy resin, it is not particularly limited
Brominated epoxy resin alone or other bromine
Epoxy resin or non-brominated epoxy resin, etc.
Use one or two or more kinds as appropriate.
Is possible.

Typical examples of the brominated epoxy resin include a brominated bisphenol A type epoxy resin, a brominated phenol novolac type epoxy resin, and a reaction product of a polyfunctional epoxy resin and tetrabromobisphenol A. Examples of the non-brominated epoxy resin include bisphenol A-based, bisphenol F-based, biphenyl-based, novolac-based, polyfunctional phenol-based, naphthalene-based, glycidyl amine-based, glycidyl ester-based, alicyclic and alcohol-based.

When an epoxy resin having an average epoxy equivalent of 500 or more is used, impregnation into the fibrous base material becomes poor, and the appearance of the prepreg remarkably deteriorates. Further, when the average bromine content in all epoxy resins is 30% by weight or less, it becomes difficult to maintain flame retardancy in the entire resin composition (IV).

Some epoxy resins have a secondary hydroxyl group in the molecule. Since the dielectric constant and dielectric loss tangent of the resin composition (IV) are larger than desired values when there are many highly polarized functional groups such as hydroxyl groups, the average hydroxyl group concentration in all epoxy resins is 1 × 10 ^-3 mol / g. Must be:

The epoxy resin curing agent (II) of the present invention is a copolymer resin obtained by using styrene and maleic anhydride as essential components, and the molar ratio of styrene and maleic anhydride is 9: 1 to 5: 5, An acid value of 100 to 600 mg KOH / g, a number average molecular weight of 1000 to 3000, a copolymer having at least one acid anhydride group in one molecule as a main curing agent, The molar ratio is in the range of 0.3 to 1.5.

Specific examples thereof include SMA 1000A (melting point 160 ° C., glass transition temperature 154 ° C., acid value 480 mgKOH / g), 2000A (melting point 15; manufactured by Elf Atchem.
0 ℃, glass transition temperature 124 ℃, acid value 355 mgKOH /
g) and 3000 A (melting point 123 ℃, glass transition temperature 125 ℃,
The acid value is 285 mgKOH / g).

When the molar ratio of the acid anhydride group to the epoxy group is less than 0.3, the improvement in the dielectric property is little and the effect of the invention disappears. If the molar ratio exceeds 1.5, unreacted groups remain in the resin composition, resulting in a decrease in moisture resistance, and an increase in the amount of high molecular weight, resulting in poor impregnation into the fibrous base material. Further, when the number average molecular weight is 1000 or less, the crosslink density of the cured resin decreases, so that the effect of improving heat resistance cannot be obtained, and when the number average molecular weight is 3000 or more, the viscosity of the varnish increases and impregnation into the substrate decreases.

If necessary, a known epoxy resin curing agent (an acid anhydride, a phenol compound, an amine compound, etc.) may be used in combination with the above-mentioned polymer as long as the desired properties are not impaired. It is possible.

In the present invention, the curing rate of the resin composition is
It does not interfere with the addition of curing accelerators for proper adjustment. These are not particularly limited as long as they are commonly used as a curing accelerator for epoxy resins. Representative examples include imidazoles and their derivatives, tertiary amines and the like.

The flexibility-imparting agent (III) of the present invention is added to a composition comprising the epoxy resin (I) and the curing agent (II) in an amount of up to 40% by weight so that the glass transition temperature is 10 to 20. A compound that can be lowered by ° C. The epoxy resin (I) and the curing agent (I
A thermoplastic resin, a thermoplastic elastomer, or a reactive elastomer having a glass transition temperature lower than that of the cured product of I) is applicable.

A typical representative example of the thermoplastic resin comprises bisphenol A and epichlorohydrin,
Substantially linear high molecular weight epoxy resin, and its bromide, polycarbonate resin, polyester resin, polyamide resin, polymethylmethacrylate, polyalkylene glycol, chlorinated polypropylene, ketone resin,
Examples thereof include xylene resin, petroleum resin, and low polymers thereof. Among them, the high molecular weight epoxy resin has good compatibility with the epoxy composition and also improves the adhesive strength, and thus can be preferably used.

Specific examples of the thermoplastic elastomer include polybutadiene elastomer, styrene butadiene copolymer, styrene butadiene ethylene copolymer, ethylene propylene diene terpolymer, acrylonitrile butadiene copolymer, silicone resin, polyester elastomer, styrene butadiene styrene copolymer, styrene. Isoprene styrene copolymer,
Examples thereof include styrene-propylene copolymer, oil-added styrene-butadiene copolymer, caprolactone type urethane elastomer, adipate type urethane elastomer, ether type urethane elastomer, polyester type polyamide elastomer and polyol type polyamide elastomer. Among them, acrylonitrile butadiene copolymer has good compatibility with the epoxy composition and also has improved adhesive strength, and therefore, can be preferably used.

Specific examples of the reactive elastomer include epoxy-modified polybutadiene, maleic anhydride-modified polybutadiene and phenol-modified polybutadiene.
Terminal carboxy polybutadiene, terminal amino polybutadiene, epoxy modified acrylonitrile butadiene copolymer, maleic anhydride modified acrylonitrile butadiene copolymer, phenol modified acrylonitrile butadiene copolymer, terminal carboxy acrylonitrile butadiene copolymer, terminal amino acrylonitrile butadiene copolymer, hydroxyl group terminated silicone elastomer, epoxy modified silicone elastomer, Amino-terminated silicone elastomer, acid anhydride modified silicone elastomer Polyolefin glycol, polyoxyalkylene amines, urethane modified epoxy resin, lactone modified epoxy resin, hydroxyl group terminated polycaprolactone, polypropylene glycol modified epoxy resin, polysulfide modified epoxy resin, etc. Is mentioned. In addition, since monofunctional acts as a reactive diluent and adversely affects the chemical resistance and water resistance of the cured product, it is desirable to have two or more functional groups in one molecule.

The flexibility-imparting agent has a glass transition temperature of 10 ° C. to 20 ° C. of a cured product of the epoxy resin (I) and the curing agent (II).
The kind and blending amount can be selected so as to lower the temperature and maintain a desired dielectric constant and dielectric loss tangent. On the other hand, if the blending amount exceeds 40% by weight, the dielectric properties may be deteriorated, it may be difficult to maintain the flame retardancy, and the viscosity of the varnish may deteriorate the coatability of the prepreg.

When the glass transition temperature is lowered from 10 ° C. to 20 ° C., the bending elastic modulus is reduced, the toughness of the cured product is improved, and the cracks during machining are reduced. Especially, the inner wall roughness at the time of drilling a hole is reduced, and the insulation reliability of the circuit and the connection reliability of the through hole are improved. Decrease in glass transition temperature is 10 ℃
If it is less than the above range, the toughness is insufficiently improved, and if it is 20 ° C. or more, the heat resistance of the rigid substrate is insufficient.

The solvent (IV) of the present invention has a boiling point of 100 ° C. or higher,
Preferably, at 120 ° C or higher, the resin (I) and the curing agent (II)
And an organic compound (good solvent) that readily dissolves the styrene compound (III). As typical examples, methyl isobutyl ketone, toluene, xylene, dimethylformamide, propylene glycol methyl ether acetate, propylene glycol propyl ether, propylene glycol butyl ether, dipropylene glycol dimethyl ether, 3-methylmethoxybutanol,
Propylene glycol ethyl ether acetate, dipropylene glycol methyl ether and the like can be mentioned, and they can be used alone or in admixture of two or more. If necessary, other types of solvents having a boiling point of less than 100 ° C. may be used together within a range that does not impair the appearance of the obtained prepreg.

In the present invention, it is possible to add a dye, a pigment and the like to the resin composition as long as the desired properties are not impaired.

Further, a UV absorber, a fluorescent brightening agent, a photopolymerization initiator, an antioxidant and the like can be added to the resin composition as long as the desired properties are not impaired. If these are well known and commonly used,
There is no particular limitation. Typical examples thereof include an ultraviolet absorber such as a benzotriazole type, a fluorescent brightening agent such as a stilbene derivative, a photopolymerization initiator such as a thioxanthone type, and an antioxidant such as a hindered phenol type.

A substrate is impregnated with a resin composition containing the resin (I), the curing agent (II), the flexibility-imparting agent (III) and the solvent (IV) as essential components and dried, The prepreg of the present invention is produced by appropriately converting to a B-stage. As the base material of the present invention, those used in various known electric laminates can be used.

Typical examples of the material are E, D,
Examples thereof include inorganic fibers such as S and Q glass, organic fibers such as polyimide, polyarylate and tetrafluoroethylene, and a mixture thereof. Base materials using these include woven fabrics, non-woven fabrics, rovings, chopped strand mats and surfacing mats depending on their shapes, but the above-mentioned types and shapes are appropriately selected depending on the intended use and performance of the molded product. If necessary, they can be used alone or as a mixture of two or more kinds and shapes. The thickness is not particularly limited, but usually 0.03 to 0.5 mm can be used, and those subjected to surface treatment with a treatment agent typified by a silane coupling agent and those subjected to mechanical opening treatment are impregnable It is more preferable in terms of improvement.

The amount of resin impregnated into the base material is such that the resin content in the prepreg after drying is in the range of 20 to 90% by weight, and the base material is impregnated and coated and then dried at 100 to 200 ° C. It is obtained by a method such as drying for 0.5 to 30 minutes in a machine and semi-curing (B-stage).

The laminated plate of the present invention is formed by laminating using the prepreg of the present invention described above. Specifically, a plurality of the prepregs of the present invention are appropriately stacked, and laminated and molded with a configuration in which a metal foil such as copper or aluminum is placed on one side or both sides, if desired.

The metal foil is not particularly limited as long as it is used for electric laminates. In addition, laminated molding is
Usual laminating methods such as electric laminated plates and multilayer plates can be applied, for example, multi-stage press, multi-stage vacuum press, continuous molding,
Using autoclave molding, etc., temperature 100 ~ 200 ℃,
The pressure is in the range of ^{2 to} 100 kg / cm ² , and 0.03 to 3 hours. In addition, a multilayer printed wiring board having an insulating layer having a low dielectric constant and a low dielectric loss tangent can be manufactured by stacking and thermoforming in combination with an ordinary or a printed wiring board for an inner layer which is a laminated board according to the present invention.

[0034]

【Example】

 Example 1 Obtained with styrene and maleic anhydride as essential components
Copolymer resin (SMA1000A) 35% by weight in dimethylform
Add little by little to the amide (boiling point 153 ° C), and all the amount is even
The mixture was stirred with a speed mixer until it was completely dissolved. Next
Alkylphenol novolac epoxy resin and TE
Epoxy resin which is a reaction product of trabromobisphenol A
Fat (LDX4127, epoxy equivalent 395, bromine content 27 weight
%, Hydroxyl group concentration about 3.5 x 10^-Fourmol / g, Sumitomo Chemical
35% by weight of Tetrabromobisphenol
A diglycidyl ether (Epiclon 152, epoxy
Amount 360, bromine content 45% by weight, Dainippon Ink and Chemicals, Inc.
30% by weight (average epoxy equivalent of two epoxy resins)
Amount 379, bromine content 35%, average hydroxyl group concentration 2.6 x 10 ^-Fourm
ol / g), a high molecular weight epoxy resin as a flexibility-imparting agent
(H360, manufactured by Dainippon Ink and Chemicals, Inc.)
Add and continue mixing and stirring, and at the time of uniform mixing, speed
It was taken out from the mixer to obtain a varnish.

This varnish was diluted with methyl ethyl ketone, impregnated and coated on glass cloth (E glass, thickness 0.1 mm), and dried at 150 ° C. for 5 to 10 minutes to prepare a tack-free prepreg having a resin content of 45% by weight. Got Next, seven of the prepregs were stacked, and electrolytic copper foils having a thickness of 18 μm were stacked on top and bottom, heated at a pressure of 5 N / cm ² and a temperature of 130 ° C. for 30 minutes, and further pressed at 220 ° C. for 1 hour to obtain a laminated plate. The physical properties of the produced double-sided copper clad laminate were measured and are shown in Table 1.

Example 2 Using xylene as a solvent, a copolymer resin (SMA3000
A) 40% by weight, tetrabromobisphenol A diglycidyl ether (Epiclone 152) 45% by weight, cresol novolac epoxy resin (ESCN220 F, epoxy equivalent 212, Sumitomo Chemical Co., Ltd.) 10% by weight, (two types of epoxies) Resin average epoxy equivalent 333, bromine content 37% by weight, average hydroxyl concentration about 1.2 x 10 ^-4 mol / g), phenol novolac resin (Phenolite TD2093, hydroxyl equivalent 104, Dainippon Ink and Chemicals, Inc.) 5 % By weight, 15% by weight of acrylonitrile butadiene copolymer (N-220 S, manufactured by Nippon Synthetic Rubber Co., Ltd.) as a flexibility-imparting agent, 2-
A varnish was obtained in the same manner as in Example 1 except that 0.05% by weight of ethyl 4-methylimidazole was added. A laminated board was obtained in the same manner as in Example 1 except that this varnish was used, and its physical properties were measured and shown in Table 1.

Example 3 Using dimethylformamide as a solvent, 40% by weight of copolymer resin (SMA2000A), brominated phenol novolac epoxy resin (BREN-S, epoxy equivalent 285,
Bromine content 35% by weight, hydroxyl group concentration 0.1 × 10 ^-4 mol / g
Hereinafter, 60% by weight of Nippon Kayaku Co., Ltd., a terminal carboxypolybutadiene (CTB2000 × 162) as a flexibility-imparting agent,
Ube Industries, Ltd. 10% by weight and 2-ethyl 4-methylimidazole 0.02% by weight were added, and a varnish was obtained in the same manner as in Example 1. A laminated board was obtained in the same manner as in Example 1 except that this varnish was used, and its physical properties were measured and shown in Table 1.

Example 4 Propylene glycol methyl ether acetate (boiling point: 146 ° C.) was used as a solvent, and a copolymer resin (SMA3000
A) 49% by weight, tetrabromobisphenol A diglycidyl ether (Epiclone 152) 48% by weight, bisphenol A diglycidyl ether (Epicoat 828, epoxy equivalent 189, manufactured by Yuka Shell Epoxy Co., Ltd.) 3% by weight
(The average epoxy equivalent of the two epoxy resins is 350, the bromine content is 42% by weight, the average hydroxyl group concentration is about 1.5 × 10 ^-4 mol
/ G), 20% by weight of polytetramethylene glycol (PTMG1300, manufactured by Mitsubishi Chemical Corporation) as a flexibility-imparting agent, 2
A varnish was obtained in the same manner as in Example 1 with the addition of 0.03% by weight of -ethyl-4-methylimidazole. A laminated board was obtained in the same manner as in Example 1 except that this varnish was used, and its physical properties were measured and shown in Table 1.

Example 5 As a solvent, 3-methylmethoxybutanol (boiling point 174
45% by weight of copolymer resin (SMA2000A), 46% by weight of tetrabromobisphenol A diglycidyl ether (Epiclone 152), brominated bisphenol A epoxy resin (Epicoat 5048, epoxy equivalent 675, bromine content 25%) %, Manufactured by Yuka Shell Epoxy Co., Ltd. 9% by weight (average epoxy equivalent of two kinds of epoxy resins 412,
Bromine content 41% by weight, average hydroxyl group concentration about 4.1 × 10 ^-4 mo
1 / g), 15% by weight of maleic anhydride-modified polybutadiene (BN-10015, manufactured by Nippon Soda Co., Ltd.) as a flexibility-imparting agent, and 0.05% by weight of dimethylbenzylamine were added to the varnish in the same manner as in Example 1. Got A laminate was obtained in the same manner as in Example 1 except that this varnish was used, and the physical properties were measured,
The results are shown in Table 1.

COMPARATIVE EXAMPLE 1 Maleic anhydride-modified polybutadiene (B
A laminated board was obtained in the same manner as in Example 5 except that N-1015) was not blended. The physical properties of this are shown in Table 1.

Comparative Example 2 Polytetramethylene glycol (PTM) as a flexibility-imparting agent
A laminated board was obtained in the same manner as in Example 4 except that the blending amount of G1300) was changed to 50% by weight. The physical properties of this are shown in Table 1.

Comparative Example 3 In Example 5, copolymer resin (SMA2000A) was added to 34% by weight, tetrabromobisphenol A diglycidyl ether (Epiclone 152) was added to 35% by weight, and brominated bisphenol A epoxy resin (Epicoat 5049). , Epoxy equivalent 745, bromine content 26% by weight, Yuka Shell Epoxy Co., Ltd. 31% by weight (average epoxy equivalent 540 of two kinds of epoxy resins, bromine content 36% by weight, average hydroxyl group concentration about 9.3 × A laminated plate was obtained in the same manner except that the amount was changed to 10 ⁻⁴ mol / g). The physical properties of this are shown in Table 1.

Comparative Example 4 DMF was used as a solvent and 2% by weight of dicyandiamide,
Brominated bisphenol A epoxy resin (Epicoat
5048) 90% by weight, cresol novolac epoxy resin (ESCN220 F) 10% by weight, (average epoxy equivalent of two types of epoxy resin 628, bromine content 23% by weight, average hydroxyl group concentration about 1.6 x 10 ^-3 mol / g) , 2-ethyl 4-
A varnish was obtained in the same manner as in Example 1 except that 0.02% by weight of methylimidazole was added. A tack-free prepreg was obtained in the same manner as in Example 1 except that this varnish was used. A laminate was obtained in the same manner as in Example 1 except that the pressing temperature was changed to 130 ° C. for 30 minutes and 180 ° C. for 90 minutes, and the physical properties were measured.

[0044]

[Table 1] Examples and comparative examplesExample Comparative example No 1 2 3 4 5 1 2 3 4 Glass-transition temperature^{* 1} 206 190 208 184 200 220 165 190 165 Flexural modulus^{* 2} 2.2 2.3 2.3 2.0 2.2 2.5 1.8 2.1 2.0 Inner wall roughness^{* 3} 28 30 29 26 28 40 22 26 28 Flammability (UL94) V0 V0 V0 V0 V0 V0 HB V0 V0 Dielectric constant^*Four 4.4 4.3 4.0 4.3 4.0 4.2 4.7 4.5 4.9 Dielectric loss tangent^*Four 0.007 0.008 0.004 0.008 0.005 0.006 0.012 0.010 0.012 Appearance of prepreg ^{* 5} ○ ○ ○ ○ ○ ○ × × ○ Note) * 1: The glass transition temperature is measured by the DMA method. Unit: ° C * 2: JIS C6481 compliant Unit: MPa * 3: 0.9φ drill Rotation speed 60 krpm Feed rate 3.6 m / min. Average value of maximum roughness of each hole after bias cutting Unit μm * 4: Dielectric constant and dielectric loss tangent were measured at 1MHz in normal condition. * 5: The appearance of the prepreg was visually observed and judged according to the following criteria. ◯: The surface shape is smooth and there are no residual bubbles. X: Many surface irregularities. Many residual bubbles.

Example 6 Using the laminated plates obtained in Example 5 and Comparative Example 1, a through hole connection reliability test was conducted. Using a pattern in which 5,000 through holes of 0.4 φ are drilled on each laminated board, MIL
100 cycles of thermal shock were applied according to P-55110 D 4-8-6-1. Table 2 shows the change in the through-hole conduction resistance value before and after the thermal shock.

[0046]

[Table 2] Conduction resistance (mΩ) Change rate Initial value After 100 cycles (%) Example 5 248 247 -0.4 Comparative Example 1 253 274 +8.3

[0047]

INDUSTRIAL APPLICABILITY The resin composition according to the present invention has good impregnation and coating properties on a fibrous base material, and an electrical laminate using the prepreg has dielectric properties, heat resistance, machinability and It can be seen that it exhibits excellent performance with respect to combustion resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Ogima 6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory

Claims (6)

[Claims] 1. An epoxy resin (I) styrene and maleic anhydride, which is one or two or more epoxy resins having two or more epoxy groups in one molecule, at least one of which is brominated. A copolymer having an acid as an essential component, an epoxy resin curing agent (II) by blending the epoxy resin (I) and a composition comprising the curing agent (II) into a glass transition temperature of 10 to 20 ° C. A flexibility-imparting agent (III) which can be reduced, and a resin (I) having a boiling point of 100 ° C. or more, and a curing agent (II)
And a prepreg obtained by impregnating a base material with an epoxy resin composition containing the solvent (IV) of the flexibility-imparting agent (III) as an essential component. 2. The resin (I) having an average bromine content of 30% by weight or more, an average epoxy equivalent of 500 or less, and an average hydroxyl group concentration of 1 × 10 ⁻³ mol / g or less. The prepreg according to Item 1. 3. The curing agent (II) has a composition ratio of styrene and maleic anhydride of 9: 1 to 5: 5 and an acid value of 100 to 600 mgK.
The prepreg according to claim 1, which is a copolymer having OH / g, a number average molecular weight of 1000 to 3000, and at least one acid anhydride group in one molecule. 4. When the total amount of epoxy groups of the epoxy resin (I) is A and the amount of acid anhydride groups of the curing agent (II) is B,
The prepreg according to claim 1, wherein A: B = 1: 0.3 to 1: 1.5. 5. The content of the flexibility-imparting agent (III) is 40% by weight or less based on the total weight of the resin (I) and the curing agent (II). The prepreg according to Item 1. 6. A laminate having a low dielectric constant, a low dielectric loss tangent, and a high heat resistance, which is obtained by laminating and molding the prepreg according to claim 1, 2, 3, 4 or 5.